Fetal development - the key to lifetime health: The importance of studies in the nonhuman primate fetus

Mammals pass more biological milestones before birth than during the rest of their lives. Critical developmental phases are windows of potential susceptibility to adverse epigenetic influences that may predispose it to chronic diseases e.g. hypertension, obesity, and diabetes. The controlled animal studies to evaluate normal and abnormal fetal development have been conducted in rodent or sheep models. There are, however, considerable differences in pregnancy in primates and other species. Rodents are polytocus species delivering as many as 16 altricial pups which with their placentas constitute a biomass equivalent to a woman delivering a sixty pound baby. Many stages of development that are fetal in precocial species occur post-natally in rodents when oxygenation, metabolic and hormonal status differ significantly. This presentation will review comparative aspects of various pregnancy models. There are many advantages and disadvantages to the study of fetal primates compared with other species. The disadvantages include the complexity of management systems required to maintain and study animals. The advantages include the similarities to human physiology and existence of many human reagents that cross react in nonhuman primate tissues. I will use two examples, the role of estrogens in labor and delivery and development of the fetal IGF system both in normal control and nutrient restricted fetuses.